Curve responsive tilt control device

ABSTRACT

Control signals are generated from a gyroscope in response to the curvilinear movement of the vehicle corresponding to angular acceleration and angular velocity of the vehicle. In response to the angular acceleration and velocity signals direction actuating signals are generated from two pair of AND circuits connected to two OR circuits with the direction actuating signals controlling the air cushion suspension to tilt the vehicle in the proper direction when travelling a curvilinear path. There is also released an actuating signal to block the operation of the level control of the vehicle. A pendulum generates deflection signals corresponding to the direction of deflection and these deflection signals together with angular velocity signals are fed into a switching device which blocks the release of the level control blocking signals upon receiving simultaneously pendulum deflection and angular velocity signals corresponding to the same direction of curvilinear movement.

United States Patent Strohmer et al.

[451 Sept. 5, 1972 [54] CURVE RESPONSIVE TILT CONTROL DEVICE [72]Inventors: Alfred Strohmer; Joachim Ran, both of Munich, Germany [73]Assignee: Knorr-Bremse Gmbl-l, Germany [22] Filed: Jan. 26, 1971 [21]Appl. No.: 109,897

2,960,349 11/1960 Vogel ..280/1 12 A Primary Examiner-Drayton E. HoflmanAssistant Examiner-George H. Libman Attorney-Edmund M. Jaskiewicz D.C.GENERATOR SIGNAL GENERATOR [57] ABSTRACT Control signals are generatedfrom a gyroscope in response to the curvilinear movement of the vehiclecorresponding to angular acceleration and angular velocity of thevehicle. In response to the angular acceleration and velocity signalsdirection actuating signals are generated from two pair of AND circuitsconnected to two OR circuits with the direction actuating signalscontrolling the air cushion suspension to tilt the vehicle in the properdirection when travelling a curvilinear path. There is also released anactuating signal to block the operation of the level control of thevehicle. A pendulum generates deflection signals corresponding to thedirection of deflection and these deflection signals together withangular velocity signals are fed into a switching device which blocksthe release of the level control blocking signals upon receivingsimultaneously pendulum deflection and angular velocity signalscorresponding to the same direction of curvilinear movement.

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CURVE RESPONSIVE TILT CONTROL DEVICE The present invention relates torailway vehicles having air cushion suspension systems, moreparticularly, to a tilt control system responsive to a curvilinear pathfollowed by the vehicle to actuate the air cushion suspension system totilt the vehicle in the proper direction independently of the speed ofthe vehicle.

Air cushion suspension systems having a level regulator and a curvatureresponsive control for the heights of the cushion bellows have alreadybeen incorporated in railway vehicles. Such a system generally comprisesa compressor for pumping air from the air cushion bellows on the insideof the durve to the bellows on the outside of the curve in response tocurvilinear travel of the vehicle. The compressor is generally aturbo-compressor and is connected in series with the air cushion bellowson both sides of the vehicle. The compressor is driven by an electricmotor whose starting, stopping and direction of rotation is controlledby contacts actuated by the swinging movement of a pendulum mounted inthe vehicle. The shut-off valve is opened only while the compressor isrunning. The curvature responsive control mechanism comprises a pendulummounted in the vehicle so as to swing in a plane transverse to thelongitudinal direction of the vehicle. When the vehicle travels along acurve, the pendulum will swing outwardly under centrifugal force andwill thus actuate contacts to start the electric motor rotating in theproper direction so that air will be pumped from the air cushion bellowson the inside of the curve to the bellows on the outside of the curve.This transfer of the air will thus decrease the height of the bellows onthe inside of the curve and increase the height of the bellows on theoutside. As a result of the change in height of the bellows, the vehiclebody will be tilted toward the inside of the curve. The compressor willcontinue to deliver air to the outside bellows until either the verticalaxis of the vehicle becomes parallel to the pendulum or until themaximum inclination of the vehicle body has been reached and a limitswitch stops further delivery of the air.

Such a curvature responsive control device has a, number ofdisadvantages. Since the pendulum is susceptible to swinging movement byevery momentary acceleration of the vehicle produced by irregularitiesin the road bed or vibrations of the vehicle, it is necessary tosuppress the movement of the pendulum. In order to screen out suchmomentary swinging movements caused by lateral vibrations of shortduration it has been proposed to connect retarding members on thecontacts of the pendulum to delay a signal being transmitted until afterthe outward swing of the pendulum continues beyond a predeterminedperiod of time. Since with these retarding and delaying devices thecompressor will not be energized until sometime after the vehicle hasentered a curve, it is apparent that the tilting of the vehicle bodytoward the inside of the curve will be correspondingly delayed. Duringthe elapse of time from the entry of the vehicle into the curve untilthe tilting begins, passengers in the vehicle will be subjected to acentrifugal force toward the outer periphery of the curve. As thevehicle leaves the curve the centrifugal force on the pendulum willdecrease. However, if the tilt limiting mechanism becomes actuatedbefore the vehicle emerges from the constant radius portion of the curvethe pendulum will remain in its inclined position. Since the tiltingmoment exerted by the air cushion upon the vehicle body will remainconstant but the centrifugal forces acting upon the vehicle body willdecrease the vehicle body will tend to swing in an undesired mannertoward the inside of the curve. Because of this further tilting and thesubsequent decrease of the centrifugal force of the pendulum, beingsubjected to the delayed action, will return from its outwardly swungposition to its mid-position. During this movement of the pendulum,however, there will not be any return of the vehicle body to itsvertical upright position. The compressor will not begin to pump airfrom the outside bellows to the inside bellows in response to signalsfrom the pendulum after the elapse of the delay time until after thependulum, in response to a termination of the tilting of the vehiclebody, swings outwardly in opposite direction. As the air is pumped backinto the inside bellows, the vehicle body will be returned to itsupright position. It is now apparent that the passengers who have beenpreviously subjected to a cen gal force toward the outside of the curvebecause of the limitation on the maximum tilt of the vehicle will now besubjected to a force directed toward the inside of the curve as a resultof an increase in the tilt of the vehicle body as it leaves the curve.This change of direction in the centrifugal force produces disagreeableand uncomfortable effects in the passengers.

The above mentioned disadvantages and difficulties are inherent incurvature responsive control devices wherein a pendulum is employed toindicate the curvilinear path of the vehicle. For precise tilting of arail way vehicle having an air cushion suspension a gyroscope wasemployed as a curvature responsive device to generate an actuatingsignal for tilting of the vehicle as soon as the path of the vehiclechanges from a straight line to a curvilinear one. At the same time, theair cushion suspension system received an actuating signal whichdisengaged the level regulating control for the vehicle body so as toavoid any reverse tilting of the body. The signal for actuating thetilting mechanism was stopped before the vehicle left the transitionalportion of the curve and entered the constant radius portion because asthe vehicle travels along a path of constant radius the centrifugalforce remained constant. As the vehicle proceeded from the curve ontothe straight portion of the road bed the control mechanism delivered airto the air cushion suspension system to return the vehicle body into theupright position. This actuating signal together with the signal fordisengaging the level regulator of the air cushion suspension systemterminated before the vehicle left a transition portion of the curve toenter a straight track. The gyroscope as a control device generatedthese actuating signals with the relationship to the curvilinear andrectilinear movement of the vehicle as described above and was thussatisfactory in controlling the tilting of the vehicle.

Such a tilt control system could be modified so as to be independent ofthe air cushion system by providing special cylinders actuated bycompressed air or hydraulic fluid. Furthermore, actuating signalsgenerated under these mentioned conditions may also be employed forcontrolling the coupling device of a railroad vehicle, a rotary support,or a running axle precisely in response to the curvature of the roadbed.

The tilt control system utilizing a gyroscope also employed a pendulumbut merely to prevent over-controlling while the vehicle traveled alonga path which was only slightly curved. As the vehicle entered a curve,actuationg signals were released which tilted the vehicle toward theinside of the curve until the vertical central longitudinal plane of thevehicle returned to a position parallel to the pendulum. As soon as thiscondition was reached by the vehicle, the pendulum ceased the release ofits actuating signal.

It has now been determined that when the vehicle reduces its speedduring passage through a curve, and as a consequence, the centrifugalforce acting on the rear vehicle is reduced, the tilting action inresponse to the control device tends to tilt the vehicle toward theinside of the curve to a much greater extent than would be desirable.Actually, under such conditions, it would be desirable to introduce acertain degree of tilting of the vehicle back toward its verticalupright position. Also, in the situation where the exit transition curvefrom a constant radius portion of a curve to a straight section of trackhas only a small variation in its radius of curvature the control devicemay not be sufficiently sensitive to release a measurement signalindicating angular acceleration of the vehicle. As result, the tiltingforces introduced by the control device continues and effects a furthertilting of the vehicle which is undesirable.

A somewhat similar unsatisfactory operation may also occur where thetilt control mechanism of the vehicle possesses a fluid system which maybe slightly defective in that leaks are present. For example, if an aircushion suspension system of the vehicle is utilized as the tiltingstructure as described above, a slight leaking of the air spring bellowson the inside of the curve may lead to an excessively great tilting ofthe vehicle which would be undesirable.

It is therefore the principal object of the present invention to providea novel and improved curve responsive device for controlling the tiltingof railway vehicle provided with air cushion suspension system whereinthe device is sufficiently sensitive to control the tilting of thevehicle at slow curvilinear speeds or where there is only slightvariation of the radius of curvature.

It is an additional object of the present invention to provide a curveresponsive tilt control device as described above which eliminatesexcessively great or excessively long periods of time of tilting of thevehicle toward the inside of the curve.

The objects as stated above are achieved in a curve responsive tiltcontrol device for a railway vehicle having an air cushion suspensionsystem and a measuring device that generates control signals while thevehicle is travelling a curvilinear path. According to one aspect of thepresent invention there is provided means including a gyroscoperesponsive to the angular velocity and angular acceleration of thevehicle about its vertical axis for delivering separate signalscorresponding to the directions of the effects of said angular velocityand angular acceleration. A pendulum is suspended in the vehicle and isdeflectable transversely to the direction of travel of the vehicle.Responsive to the movement of the pendulum is means for generatingsignals corresponding to the direction of deflection of the pendulum.Signal modulator means are connected to the signal delivering means andto the pendulum responsive means for delivering actuating signals tocontrol the air cushion suspension to tilt the vehicle in the properdirection depending upon the direction of curvilinear travel of thevehicle and for releasing an actuating signal (S to block the operationof the level control of the vehicle. Swiching means are connected to thesignal delivering means and to the pendulum responsive means forblocking the release of the actuating signal (S in response to receivingsimultaneously a signal corresponding to the angular velocity and asignal from the pendulum responsive means indicative of a deflection ofthe pendulum in a direction corresponding to the direction of theangular velocity.

Further according to the present invention the deflection of thependulum may generate first and second positive measurement signals andthe angular velocity responsive means generates first and second angularvelocity signals with the first signals corresponding to curvilineartravel in one direction and the second signals to curvilinear travel inthe other direction. A first AND circuit receives the first angularvelocity and first pendulum deflection signals and a second AND circuitreceives the second angular velocity and the second deflection signals.A NOR circuit is connected to the outputs of the first and second ANDcircuits and a third AND circuit is connected to transmit the actuatingsignal (S and to the output of the NOR circuit.

Other objects and advantages of the present invention will be apparentfrom the accompanying description when taken in conjunction with thefollowing drawings, which are exemplary, wherein;

FIG. 1 is a schematic representation of the control device according tothe present invention;

FIG. 2 is' a schematic representation showing the several elements ofthe present invention mounted in a railway vehicle provided with an aircushion suspension system; and

FIG. 3 is an electrical diagram showing the connec tions within theswitching device of FIG. 1.

Proceeding next to the drawings wherein like reference symbols indicatethe same parts throughout the various views a specific embodiment andmodification of the present invention will be described in detail.

In FIG. 1 there is indicated at 1 an enclosed gyroscope mounted in avehicle with its measuring axis being vertical and its axis of rotationbeing horizontal and transversely of the longitudinal axis of thevehicle. The gyroscope is connected to a measuring device 2 whichgenerates two different signals +1 and w in response to the directionsof turning movements of the vehicle about its vertical axis as indicatedby the gyroscope 1. Measuring device 2 also generates angularacceleration signals +0: and a in response to the control signalsgenerated from the gyroscope. The gyroscope l and measuring instrumentmay be those manufactured by Teldix of Heidelberg, West Germany.

The signals from measuring device 2 indicating angular acceleration andangular velocity of turning move ment are transmitted by conductors 3,4, 5 and 6 to a switching device 7 which has two switching positions andis shown in greater detail in FIG. 4. When the vehicle travels in theforward direction, switching device 7 will be in the first switchingposition but upon reverse movement of the vehicle the switching devicewill be transposed into its second switching position. In its firstswitching position, the signals +m m +11 and -a are transmitted toconductors 8, 9, and 11 respectively. In the second switching position,conductors 3 and 4 which transmit signals +1 and w are transposed totransmit these signals to the conductors 9 and 8, respectively. In asimilar manner, in the second switching position the switching device 7transposes the connections of conductors 5 and 6 to conductors 11 and 10respectively. The switching device 7 is controlled through conductor 12by the polarity of a voltage generated by a DC. generator 13 which isdriven in a known manner by an axle of wheel of the vehicle.

There is an electrical lead 14 branching off from the conductor 12 to aswitching device 15, which, independently of the polarity of thegenerated voltage, closes a switch 18 between a constant voltage source16 and a voltage supply conductor 17 whenever the voltage lead 14exceeds a predetermined value. Since the voltage in lead 14 depends onthe r.p.m. of the DC. generator 13, switch 18 will close only after thespeed of the vehicle exceeds a certain minimum velocity. The measuringdevice 2 is supplied with electrical energy from the conductor 17.

The output conductor 8 of switching device 7 is connected to the inputof an AND circuit 19, of another AND circuit 20 and to diode 21. Theoutput conductor 9 from switching device 7 is connected to the input of30 an AND circuit 22, of a second AND circuit 23 and to a diode 24.Output conductor 10 is connected to a second input of the AND circuit 19and to a second input of AND circuit 22. Output conductor 11 isconnected to the second inputs of AND circuits 20 and 23. The diodes 21and 24 are connected to a common conductor 25 leading to the input of asignal amplifier 26.

Mounted within the vehicle is a pendulum 27 which swings in a verticalplane transverse to the longitudinal axis or direction of travel of thevehicle. Contacts 28 and 29 are closed when engaged by the outwardlyswinging pendulum. Contact 28 is closed by centrifugal force duringforward movement of the vehicle along a right turn and is connectedbetween the voltage supply conductor 17 and a conductor 30 connected toa third input of the AND circuit 19. Accordingly, upon the occurrence ofan inclining or tilting force to the left of the vehicle, conductor 30will transmit a positive measurement signal H Contact 29 which is closedduring the forward movement of the vehicle along a left turn curveconnects the voltage supply conductor 17 with a lead 31 connected to thethird input of the AND circuit 23. The lead 31 will thus carry apositive measurement signal H on the occurrence of an inclining ortilting force to the right on the vehicle.

In the operation of the control system of the copending application Ser.No. 798,405 filed Feb. 11, 1969, the pendulum functions to preventovercontrolling while the vehicle travels along paths that are onlyslightly curved. When the contacts are closed by the swinging pendulum,actuating signals will be generated in response to similarly directedangular acceleration and angular velocity signals only after thependulum has swung out in the opposite direction.

A central switch 32 is provided which is responsive to the angle betweenthe plane of the railway track and the vertical longitudinal plane ofthe vehicle. The switch is provided with contacts for interrupting theproduction of actuating signals when angular acceleration and angularvelocity signals are not in the same direction during that time that theangle between the plane of the railway track and the verticallongitudinal plane of the vehicle is at a right angle. In its openposition switch 32 breaks the connection of voltage supply 16 with lead33 connected to the third inputs of the AND circuits 20 and 22 onlyduring travel along a level road where the cushioned portion of thevehicle body is parallel to the wheel axles.

The AND circuits 19, 20, 22 and 23 have the characteristic oftransmitting a voltage signal to their respective outputs 34, 35, 36 and37 only when a signal voltage reaches all ofthe input terminalssimultaneously. The outputs 34 and 35 of AND circuits l9 and 22 areconnected to the inputs of an OR circuit 38, while the outputs 36 and 37of the two AND circuits 20 and 23 are connected to the inputs of an ORcircuit 39. The OR circuits 38 and 39 have the characteristic oftransmitting a signal to their respective outputs 40 and 42 only when asignal is received by one or both of their respective inputs. The output40 of the OR circuit 38 is connected with the input of a signalamplifier 41 and the output 42 of the OR circuits 39 is connected withthe input of a signal amplifier 43. When one of the amplifiers 26, 41 or43 receives a signal, the signal will be transmitted from its respectiveoutput 44, 45 or 46 to the coil of its respective relay 47, 48 or 49.The relay 47 which is connected to the signal amplifier 26 closes aswitch 50 when energized which in turn closes the connection of lead 52from an electric power source 51 to a conductor 53 which delivers anactuating signal S This actuating signal is delivered only when thevehicle is turning about its vertical axis but is independent of thedirection of the turn. In an air cushion suspension system having a tiltcontrol system for the vehicle body, the actuating signal S can be usedfor disconnecting or rendering inoperative the generally used levelregulating means.

Relay 48 when non-energized maintains switches 54 and 55 open. Switch 54connects lead 52 with a lead 56 for transmitting an actuating signal Sonly while the vehicle is moving with an angular acceleration about avertical axis in a predetermined direction which may be to the right.Relay switch 55 provides a connection of lead 52 with a lead 57. Therelay 49 is connected to two switches 58 and 59 which are closed onlywhen relay 49 is energized. The relay switch 58 connects lead 52 with anoutput conductor 60 which transmits an actuating signal S only duringmovement of the vehicle with angular acceleration about a vertical axisin a direction opposite to the direction set forth above or the left. Inthe above described known air cushion suspension system, the actuatingsignals S and S are transmitted, to devices which will tilt the vehiclebody in one direction during the continued transmission of one of suchsignals but will tilt the body in the other direction during thecontinued transmission of the other of such signals.

The relay switch 59 connects lead 52 with a conductor 61. The conductors57 and 61 lead to contacts 62 and 63 of relays 64 and 65 respectivelywith these contacts being closed when the relays are non-energized.

Contact 62 is connected to an output lead 66 for an actuating signal SFrom contact 63 there is an output conductor 67 delivering an actuatingsignal S The output 66 is also connected to the coil of relay 65 withthe other end of the coil being connected to ground and also connected acontact 68 which remains open while relay 65 is non-energized. Output 67is connected in a similar manner to the coil of relay 64 with the otherend of the coil being connected to ground and to a contact 69 whichremains open while the relay 64 is non-energized. Contacts 68 and 69have their other sides connected to a conductor 70 leading to output 53.

In the known air cushion suspension system, while an actuating signal Sor S is generated, the air cushion which at that time is on the outsideof the curve is connected to a level regulator which is controlled byonly the height of the longitudinal tilt axis of the vehicle.

The electrical energy supply connection to the AND circuits 19, 20, 22and 23, the OR circuits 38 and 39 and the signal amplifiers 26, 41 and43 are not shown in FIG. 1, but the necessary connections can be readilymade through leads 17 with voltage source 16.

The switching device according to the present invention comprises leads71 and 72 which branch from the conductors 3 and 4 transmitting themeasurement signals and-1o The branch leads 71 and 72 are connected tothe inputs of AND gates 73 and 74 respectively. From the lead 30 thereis connected a branch lead 75 which is connected through a time delayelement 76 to the second control input of AND gate74. From the lead 31there is connected a branch lead 77 which is similarly connected througha time delay element 78 to the second control input of AND circuit 73.The outputs of the AND circuits 73 and 74 are connected through outputleads 79 and 80 to the inputs of a NOR circuit 81. The NOR circuit 81has an output lead 82 which is connected to an input of an AND circuit83 which is connected in the output conductor 53 which generates theactuating signal S The AND circuit 83 releases the actuationg signal Sat output connection 84 only when positive signals appear both in theoutput line 53 and in line 82.

As may be seen in FIG. 2 a railway car has a body 90 supported upon aircushions 91 which are located under both sides of the body and aresupported on a beam 93 of a pivotably mounted truck 94 having wheels 92.The beam 93 is connected without any springs to the wheel 92 asindicated in the drawings. Positioned in the vicinity of the air bellows91 on the car body 90 is a control device 95 comprising a system ofpressure observation and control in the bellows 91 and as shown in thecopending application Ser. No. 808,225, now US. Pat. No. 3,572,747 filedon Mar. 18, 1969 by the same assignee as the present application. Acompressor 28 shown in FIG. 1 of the above mentioned patent applicationcan also be positioned in the control device 95 which can be driven bythe wheel 92 in combination with a universal joint shaft such as knownin accessory drives. For actuating valves 7, 8 and 43 shown in FIG. 1 ofapplication Ser. No. 808,225 control rods 96 are employed and arepositioned with respect to the beam 93 as shown in FIG. 2 of thedrawings. The central switch 32 in the present application may bepositioned in the control device 95 as to be actuated by the controlrods 96. All of the remaining elements illustrated in FIG. 1 can then becombined in a single device 97 positioned at any point within thevehicle body 90.

It is preferable to arrange the device 97 as near as possible to thehorizontal longitudinal axis of the body. The device 97 is connectedwith control device by a cable 98 which accomodates the output circuits56, 66, 67, 60 and 53 for the actuating signals as well as theconnecting leads l7 and 33 for central switch 32.

The air cushion suspension system of a vehicle to which the controlsystem of the present invention is directed is generally provided with athird centrally positioned level regulator to maintain the longitudinalaxis of tilt of the vehicle at a constant height. The air cushionbellows of the air cushion suspension system are generally characterizedby having volumes which do not increase linearly with their heights.Further, losses of air from the air cushion bellows occur duringactuation of the tilting control in response to the curvature of thepath. For these reasons, when the vehicle travels along a curve therewill occur during the tilting of the vehicle body a lowering of thelongitudinal axis about which the vehicle body is tilted. The thirdlevel regulator which is switched in when the two lateral levelregulators are disconnected will deliver compressed air into only thatbellows which is then at the outside of the curve to raise thelongitudinal axis of tilt during the tilting of the vehicle body. Theactuating signal for this third level control device is generated from aswitching system which during the actuation of an actuating signalresponsive to the angular acceleration and angular velocity but whichduring that time remains independent of the direction of turning.

During movement of the vehicle in the forward direction, switchingdevice 7, under the influence of the corresponding polarity of thevoltage produced by DC. generator 13, will keep the leads 3 and 8, 4 and9, 5 and 10 and also 6 and 1 1 connected with each other. Duringstraight line or rectilinear travel of the vehicle no forces will beexerted on the gyroscope 1 and measuring device 2 will not deliver anysignals to conductors 3-6. During such rectilinear travel pendulum 27will remain in its mid or stationary position. Contacts 28 and 29 willremain open and there will be no voltage in leads 30 and 31. The vehiclebody will be in a position parallel to the plane of the road bed so thatcentral switch 32 will not transmit any voltage through conductor 33. Asa result, no signals will be transmitted to the inputs of AND circuits19, 20, 22 and 23 and the OR circuits 38 and 39. Relay switches 50, 54and S8 and also 55 and 59 will keep the outputs 53, 56, 60, 66 and 67disconnected from the voltage source 31 and no actuating signals will bedelivered from the system.

As the vehicle leaves a straight portion of track A to enter atransition curve portion, the front end of the vehicle will experiencean angular acceleration and also an angular velocity or movement in adirection corresponding to the direction of turning. Gyroscope 1 willthus transmit control signals to measuring device 2 which in turn willgenerate indicating signals +1 and +0: into conductors 3 and 5respectively. The leads 8 and 10 will each transmit a signal to theinputs of AND circuit 19 and AND circuit 19 in turn will transmit asignal at its output 34. None of the other AND circuits 20, 22 and 23will receive any input signals and hence will not transmit any outputsignals.

The OR circuit 38 will then receive an input signal from lead 34 andwill transmit a signal through its output 40 to the amplifier 41 so asto energize the coil of relay 48. The relay switches 54 and 55 will thusbe closed and output 56 will be connected with the voltage source 51 andwill transmit an actuating signal S At the same time, the signal whichwas fed by measuring device 2 into lead 3 will be transmitted throughthe output lead 8, across diode 21 and through conductor 25 to thesignal amplifier 26 to transmit the amplified signal to relay 47 whichwill be energized to close the switch 50. This will connect the outputlead to the voltage source 51 and an actuating signal S will betransmitted through lead 70 to contact 68 and 69 of relay 64 and 65.

Also with the closing of relay switch 55 lead 57 will be connected tothe voltage source 51 and the same voltage will be transmitted acrossthe closed contact 62 of relay 64 to output lead 66 which will receivean actuating signal S The coil of relay 65 will be energized to opencontact 63 while contact 68 will be closed. The output 66 in parallelwith contact 62 will thereby be connected through contact 68, the leads70 and relay switch 50 to voltage source 51.

As described above, a vehicle having an air cushion suspension systemand a curvature responsive tilt control system may have its levelregulator controlled by the actuating signals S so that the heights ofthe air cushion bellows are kept constant. The actuating signal S caneffect a pumping of the air from the bellows on the right side of thevehicle into the bellows on the left side of the vehicle to graduallytilt the vehicle body to the right during the duration of actuatingsignal S The actuating signal S which is responsive only to the heightof the longitudinal tilting axis of the vehicle can effect a connectionbetween the third level regulator and the air cushion bellows on theleft side of the vehi- At the end of the transition portion the vehiclewill keep its maximum angular velocity for the curve. As the vehicleenters the constant radius portion the angular acceleration will drop tozero while the angular velocity remains constant. The measuring device 2will therefore continue to transmit the indicating signal +0) intoconductor 3 to indicate a right hand turning of the vehicle body whilethe signal +0: which was previously transmitted into the lead 5 willcease. The AND circuit 19 will become blocked so that no signal will betransmitted to the inputs of OR circuit 38. The OR circuit will likewisebe blocked so that there will not be any output signal at its output 40and no signal will be transmitted to relay 48 through amplifier 41. Therelay switches 54 and 55 will be opened and will disconnect the outputlead 56 from the voltage source The output signal 5,; will then stop andfurther tilting of the vehicle body on the air cushion will bediscontinued and the present angle of inclination of the vehicle bodywill be maintained. The output lead 53 and also the output lead 66 willremain connected with voltage source 51 and relay 65 will remainenergized. The actuating signals S and S,, will therefore continue asthe vehicle travels along the constant radius portion of the curve. Thethird level regulator can now regulate the height of the air cushionbellows on the side of the vehicle at the outside of the curve.

When the vehicle travels from the constant radius portion into thetransition portion at the exit of the curve, the vehicle will experiencean angular acceleration in the opposite direction from the angularacceleration experienced at the entrance to the curve. This negative ordecreasing angular acceleration will in turn decrease the angularvelocity of the vehicle. The gyroscope 1 will then transmit a controlsignal +0 into conductor 3 and a signal a into the lead 6. AND circuit20 will thus receive a signal at its inputs and will transmit an outputsignal at 36. The OR circuit 39 will now become conductive and throughlead 42 and amplifier 43 will energize the coil of relay 49. This willclose relay switches 58 and 59 to connect output lead 60 to the voltagesource 51 and an actuating signal S will be generated at the output 60.

In the air cushion suspension system, the actuating signal S willcontrol the delivery of air back from the air cushion bellows at theoutside of the curve to the bellows at the inside of the curve. Duringthis time the actuating signals S and S will continue to be generated.

When the vehicle leaves the exit transition portion and travels into thestraight portion of track the vehicle will no longer experience anyangular velocity or angular acceleration. The measuring device 2 willthen interrupt the measuring signals +0 anda in the leads 3 and 6. ANDcircuit 20 and the serially connected OR circuit 39 will both becomeblocked and relay 49 will be de-enerized. Relay switches 58 and 59 willnow open and will interrupt the connection of the output lead 60 withvoltage source 51. This will stop the generation of the actuating signalS,

At the same time, voltage will be shut off through diode 21, lead 25 andthe control input of the signal amplifier 26. Relay 47 will thus becomede-energized and relay switch 50 will open. The output lead 53 will bedisconnected from voltage source 51 and the actuating signals S will bestopped. The relay 65 is thus deenergized and output lead 60 is alsodisconnected from the voltage source 51. This will stop the generationof the actuating signal S In the vehicle air cushion suspension systemwhich is actuated by the control system disclosed as this invention theinterruption of the actuating signals S S and S will stop the pumping ofthe air from the bellows at the outside of the curve to the bellows atthe inside of the curve, will disconnect the third level regulator fromthe air cushion bellows at the outside of the curve, and willreestablish the normal operation of the lateral level regulatingdevices. If the vehicle body has not yet been brought back to itsinitial vertical position by this pumping back of the air, thisrepositioning of the vehicle body can be carried out by the laterallevel regulators.

Should the speed of the vehicle be reduced as the vehicle is passingthrough a curve while tilted, the centrifugal force on the pendulum 27will be correspondingly decreased and the pendulum 27 will be deflectedtoward the inside of the curve to close one of the contacts 28 and 29.This deflection can also be promoted by the actuation device for tiltingthe vehicle which is capable of increasing the tilt of the vehiclebecause of the reduction in centrifugal force acting on the vehicle. Ameasurement signal I-l or H will then appear in one of the leads 75 or77. The signal will be transmitted after suitable delay through delaydevice 76 or 78 to AND circuit 74 or 73. Since a measurement signal w or+1 has already been supplied to the other input of AND circuit 74 or 73over a line 72 or 71 because of the passage of the vehicle through acurve as described above, AND circuit 74 or 73 will release an outputsignal into output line 80 or 79. This output signal will induce NORcircuit 81 to block the signal previously being transmitted in line 82while the leads 79 and 80 were without any signals therein. As a result,no signal will appear at the input of AND circuit 83 through lead 82 andthe actuation signal S previously appearing on the output connection 84,will be blocked. The blocking of the actuation signal at 84 will enablethe customary level control device of the vehicle to become operativeand to tilt the vehicle toward its upright position until closed contact28 or 29 is opened by pendulum 27. When either contact 28 or 29 isopened no signal will appear in lead 75 or 77, there will not be anysignal on the inputs of NOR member 81, and the lead 82 will againtransmit a signal which will permit the release of actuating signal Sthrough AND circuit 83 at output 84. Thus, the actuating signal beingtransmitted in line 53 will no longer will be blocked in AND circuit 83and will appear at output 84. As result, when the vehicle has beenrighted into its vertical upright position wherein its vertical axis isparallel to the pendulum 27, an actuating signal S for switching off theregular level control of the vehicle will again be released.

A corresponding operating sequence will occur in the event that thevehicle should be excessively tilted as it passes through a curvebecause of any irregularities in the tilt actuation device of thevehicle. A similar sequence will also occur in the situation where thevehicle passes through a transition curve having only a very slightvariation in the radius of curvature from a curve of constant radius toa straight line. In this situation the measurement signals or a forreturning the vehicle to its vertical upright position will not occurbecause of the gyroscope 1 will not be sufficiently sensitive to respondto this slight variation in angular acceleration. However, themeasurement signals +0: and u will continue and together withmeasurement signals H or H generated by pendulum 27 will bring about atilting of the vehicle to its upright position by blocking actuatingsignal 5,, so that the regular level control of the vehicle mayfunction.

The pendulum 27, as described above, releases positive measurementsignals H and H responsive to the deflection of the pendulum. Thispendulum arrangement can be modified to interrupt or block measurementsignals when the pendulum is deflected so as to in effect releasenegative measurement signals. With such a modified pendulum arrangementit is expedient to provide three NAND circuits in place of the ANDcircuits 73 and 74 as well in place of the NOR circuit 81.

The time delay element 76 and 78 are employed to eliminate measurementsignals H,, or H of pendulum 27 that occur for only brief durations oftime and result merely from oscillations from the pendulum because ofirregularities in the road bed or normal swaying of the vehicle duringits movement thereof. A time delay of about 1.0 seconds may be employedfor the delay elements but it is to be understood that the time delayperiod may be set as desired.

The present control system can also be used for inclination or tiltingcontrol of the air cushion suspension system. The actuating signalsgenerated by the control system can also be used for curvatureresponsive tilt control of a vehicle equipped with the usual leaf orcoil springs by employing special cylinder and piston devices which onlycontrol the tilting of the vehicle body. The actuating signals may alsobe used for control the adjustment of curve axles or the turningpositions of vehicles as well as for curvature controlled vehiclecouplings.

Where the device according to the present invention releases positivemeasurement signals in-response to the deflection of the pendulum thesesignals may be combined or coordinated with each other, i.e., such as +1and H as well as -m and H so that the measurement signals for angularvelocity and for pendulum deflection are transmitted over an AND circuitand combined to an NOR circuit whose output is connected to the input ofan AND circuit connected to the output line of actuation signal S wherethis actuation signal is for blocking the operation of the level controlof the vehicle.

In a similar manner, where the deflection of the pendulum releasesnegative measurement signals, as described above, the signals responsiveto angular velocity and deflection of the pendulum, namely +w and H aswell as -m and H may be introduced into two NAND circuits whose outputsare connected over a third NAND circuit to the input of an AND circuitconnected in the output line of actuation signal S It is thereforeapparent that the present invention provides for the pendulum to operatein addition to its monitoring function, to permit the regular levelcontrol of the vehicle to become effective where there is a excessivelygreat tilting of the vehicle toward the interior of the curve. Thisregular level control functions until the vehicle is returned to itsupright position so that the vertical axis of the vehicle is parallel tothe pendulum Any tilting of the vehicle beyond its vertical uprightposition is therefore avoided. In addition, the vehicle can be returnedto its vertical upright position when the vehicle is travelling along acurved portion having such a small variation in its radius of curvaturethat the control device is not sufficiently sensitive to releasemeasurement signals responsive to angular acceleration. In thissituation, the regular level control of the vehicle will again functionto tilt the vehicle back toward its upright position.

It is understood that this invention is susceptible to modification inorder to adapt it to different usages and conditions and, accordingly,it is desired to comprehend such modifications within the invention asmay fall within the scope of the appended claims.

What is claimed is:

' 1. In a curve responsive tilt control device for a railway vehiclehaving an air cushion suspension system and a measuring device thatgenerates control signals while the vehicle is travelling a curvilinearpath, the combination of means responsive to the angular velocity andangular acceleration of the vehicle about its vertical axis fordelivering separate signals corresponding to the directions of theeffects of said angular velocity and angular acceleration, a pendulumsuspended in the vehicle and deflectable transversely to the directionof travel of the vehicle, means responsive to the deflection of saidpendulum for generating signals corresponding to the direction ofdeflection of said pendulum, signal modulator means connected to saidsignal delivering means and said pendulum responsive means fordelivering actuating signals to control the air cushion suspension totilt the vehicle in the proper direction depending upon the direction ofcurvilinear travel of the vehicle and for releasing an actuating signal(S to block the operation of the level control of the vehicle, andswitching means connected to said signal delivering means and saidpendulum responsive means for blocking the release of said actuatingsignal (S in response to receiving simultaneously a signal correspondingto angular velocity and signal from said pendulum responsive meansindicative of a deflection of the pendulum in a direction correspondingto the direction of the angular velocity.

2. In a curve responsive tilt control as claimed in claim I wherein thedeflection of the 'pendulum generates first and second positivemeasurement signals and said angular velocity responsive means generatesfirst and second angular velocity signals, the first signalscorresponding to curvilinear travel in one direction and the secondsignals to curvilinear travel in the other direction, a first ANDcircuit receiving the first angular velocity signal and the firstpendulum deflection signal, a second AND circuit receiving the secondangular velocity signal and the second pendulum deflection signal, a NORcircuit connected to the output of said first and second AND circuits,and third AND circuit connected to transmit said actuating signal (S andto the output of said NOR circuit.

3. In a curve responsive tilt control device as claimed in claim 1wherein the deflection of the pendulum generates first and secondnegative measurement signals and said angular velocity responsive meansgenerates first and second angular velocity signals, the first signalscorresponding to curvilinear travel in one direction and the secondsignals to curvilinear travel in the other direction, a first NANDcircuit circuit receiving the combined first signals and a second NANDcircuit receiving the combined second signals, a third NAND circuitconnected to the outputs of said first and second NAND circuits, and ANDan circuit connected to transmit the actuating signal (S and to theoutput of said third NAND circuit.

4. In a curve responsive tilt control device as claimed in claim 2 andcomprising time delay means connected to said pendulum signal generatingmeans for transmitting only those deflection signals which persistlonger than a predetermined duration of time.

1. In a curve responsive tilt control device for a railway vehiclehaving an air cushion suspension system and a measuring device thatgenerates control signals while the vehicle is travelling a curvilinearpath, the combination of means responsive to the angular velocity andangular acceleration of the vehicle about its vertical axis fordelivering separate signals corresponding to the directions of theeffects of said angular velocity and angular acceleration, a pendulumsuspended in the vehicle and deflectable transversely to the directionof travel of the vehicle, means responsive to the deflection of saidpendulum for generating signals corresponding to the direction ofdeflection of said pendulum, signal modulator means connected to saidsigNal delivering means and said pendulum responsive means fordelivering actuating signals to control the air cushion suspension totilt the vehicle in the proper direction depending upon the direction ofcurvilinear travel of the vehicle and for releasing an actuating signal(SN) to block the operation of the level control of the vehicle, andswitching means connected to said signal delivering means and saidpendulum responsive means for blocking the release of said actuatingsignal (SN) in response to receiving simultaneously a signalcorresponding to angular velocity and signal from said pendulumresponsive means indicative of a deflection of the pendulum in adirection corresponding to the direction of the angular velocity.
 2. Ina curve responsive tilt control as claimed in claim 1 wherein thedeflection of the pendulum generates first and second positivemeasurement signals and said angular velocity responsive means generatesfirst and second angular velocity signals, the first signalscorresponding to curvilinear travel in one direction and the secondsignals to curvilinear travel in the other direction, a first ANDcircuit receiving the first angular velocity signal and the firstpendulum deflection signal, a second AND circuit receiving the secondangular velocity signal and the second pendulum deflection signal, a NORcircuit connected to the output of said first and second AND circuits,and third AND circuit connected to transmit said actuating signal (SN)and to the output of said NOR circuit.
 3. In a curve responsive tiltcontrol device as claimed in claim 1 wherein the deflection of thependulum generates first and second negative measurement signals andsaid angular velocity responsive means generates first and secondangular velocity signals, the first signals corresponding to curvilineartravel in one direction and the second signals to curvilinear travel inthe other direction, a first NAND circuit circuit receiving the combinedfirst signals and a second NAND circuit receiving the combined secondsignals, a third NAND circuit connected to the outputs of said first andsecond NAND circuits, and AND an circuit connected to transmit theactuating signal (SN) and to the output of said third NAND circuit. 4.In a curve responsive tilt control device as claimed in claim 2 andcomprising time delay means connected to said pendulum signal generatingmeans for transmitting only those deflection signals which persistlonger than a predetermined duration of time.